346 
Barber. — Cupressinoxylon vectense. 
Tangential width of spring-tracheides in \x \ — 
Rings 
1 
2 
3 
4 
5 
6 
7 
8 
9 
10 
11 
Branch (i) 
12.5 
18-8 
20.7 
22.7 
23-7 
24-3 
2 4-5 
24 
24.7 
Branch (2) 
14 
i7-5 
20 
21 
23*5 
24 
25*5 
Root (1) 
12.7 
16 
20 
23 
23-7 
25 
24 
25.2 
24.5 
25 
24-5 
In root (2), the inner rings not being well defined, the 
tracheides were measured at about equal distances from the 
pith, and in successive rings where these were apparent. 
Root (2) | 10 | 16.5 | 21 | 24 [ 26 | 26 | 22 J 24 | 22 ft. 
We thus see that the tracheides in the first ring are very- 
small ; from the second to the sixth a rapid rise takes place, 
and from the sixth to the eleventh the tangential width is 
fairly constant. 
The radial width of the tracheides has been calculated by 
measuring the first ten tracheides in each ring in ten as 
widely separated regions of the section as possible. The 
resulting average of 100 spring-tracheides is assumed to. 
be a fair guide. The measurement is, however, rendered 
difficult by the indefinite limits of certain of the rings, and 
the consequent necessity of selecting suitable rows for 
observation. No figures could be obtained for the first few 
rings, and in root (2) it was found necessary to adopt 
another method. 
Radial width of spring-tracheides in y : — 
Rings 
1 
2 
3 
4 
5 
6 
7 
8 
9 
IO 
II 
12 
Branch (1) 
17.2 
J>- 
00 
19.1 
20-6 
21.5 
22.3 
Branch (2) 
20.4 
21 
23-3 
22-2 
Root (1) 
19.2 
19-6 
20-9 
20-3 
21-6 
22-5 
22-1 
20-5 
20-2 
